Integrated stent repositioning and retrieval loop

ABSTRACT

A braided stent having an integral retrieval and/or repositioning loop includes a plurality of wires having first and second ends interbraided in a braided pattern to form a tubular stent having opposed atraumatic first and second open ends with each open end having a circumference; wherein said first and second wires ends are disposed at said second stent open end and said wires are looped at said second stent open end so that none of the first or second wires ends are exposed at the circumference of second stent open end; wherein at least of two of said wires are formed into a repositioning and/or retrieval loop having an elongated portion circumferentially disposed at said first opposed open end; and wherein said reposition and/or retrieval loop comprises two sections which run adjacent to each other prior to crossing to permit grabbing of both sections simultaneously by a practitioner.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. ProvisionalApplication No. 60/680,689, filed May 13, 2005, the content of which isincorporated in its entirety by reference.

FIELD OF THE INVENTION

The present invention relates to devices, methods and systems forretrieval and/or repositioning of an implanted stent. More particularly,the present invention relates to implantable stents having a stentretrieval member or loop for easy retrieval and/or repositioning of theimplanted stent.

BACKGROUND OF THE INVENTION

An intraluminal prosthesis is a medical device used in the treatment ofdiseased bodily lumens. One type of intraluminal prosthesis used in therepair and/or treatment of diseases in various body vessels is a stent.A stent is a generally longitudinal tubular device formed ofbiocompatible material which is useful to open and support variouslumens in the body. For example, stents may be used in the vascularsystem, urogenital tract, esophageal tract, trachealibronchial tubes andbile duct, as well as in a variety of other applications in the body.These devices are implanted within the vessel to open and/or reinforcecollapsing or partially occluded sections of the lumen.

Stents generally include an open flexible configuration. Thisconfiguration allows the stent to be inserted through curved vessels.Furthermore, this configuration allows the stent to be configured in aradially compressed state for intraluminal catheter implantation. Onceproperly positioned adjacent the damaged vessel, the stent is radiallyexpanded so as to support and reinforce the vessel. Radial expansion ofthe stent may be accomplished by inflation of a balloon attached to thecatheter or the stent may be of the self-expanding variety which willradially expand once deployed. Structures which have been used asintraluminal vascular grafts have included coiled stainless steelsprings; helically wound coil springs manufactured from a heat-sensitivematerial; and expanding stainless steel stents formed of stainless steelwire in a zig-zag pattern.

Various techniques or systems have been proposed for retrieving and/orrepositioning an implanted stent. For example, U.S. Pat. No. 5,643,277to Soehendra et al. describes the use of a tapered, threaded cable forremoval of an implanted stent. The threaded portion of the cable isdescribed as being twisted to engage an implanted biliary stent, such asa polyethylene stent, and then pulled to remove the sent from thepatient.

U.S. Pat. No. 6,676,692 to Rabkin et al. describes a catheter systemhaving stent-capturing hooks. The hooks are described as being usefulfor engaging the stent, thereby allowing repositioning and/or retrievalof the stent.

U.S. Patent Application Publication No. 2002/0188344 A1 to Bolea et al.describes the use of hinged hooks attached to interior portions of animplantable stent. Use of a retrieval tool is described as engaging thehooks, and, upon twisting of the retrieval tool, the stent is contractedthereby allowing retrieval of the stent. In another embodiment, a wirelasso is described as being secured to an implantable stent with thewire lasso having a small loop internally disposed within the open lumenof the stent. The loop of the lasso is described as being engaged by aretrieval tool, and, upon twisting of the retrieval tool, the stent iscontracted thereby allowing retrieval of the stent. Other embodimentsinclude a lasso wire threaded through eyelets at a stent end. Aretrieval tool is described as engaging the lasso wire, and, upontwisting or axially pulling the lasso wire, the stent is contractedthereby allowing retrieval of the stent.

Prior retrieval systems may appear easy to use, but often requirecertain user-sensitive techniques, such as twisting or turning in orderto reposition or remove the stent. Moreover, in smaller stents, such asbiliary stents, the spacing between conventional stent segments isgenerally smaller than the size of standard forceps or graspers, makingit even difficult to grab a hook or lasso.

SUMMARY OF THE INVENTION

The present invention provides a stent, for example a braided stent,having an integral repositioning and/or retrieval loop. The stentincludes at least two elongate wires interlooped to form a tubular stenthaving opposed first and second open ends with each open end having acircumference, wherein one of the at least two wires is formed into arepositioning and/or retrieval loop having an elongated portioncircumferentially disposed at the first opposed open end. Desirably, theat least interlooped two wires are braided. The elongatedcircumferential portion of the reposition and/or retrieval loop mayinclude a wire loop substantially traversing the first circumference.The elongated circumferential portion of the reposition and/or retrievalloop may further include a wire loop partially traversing the firstcircumference.

Desirably, the elongated circumferential portion of the repositionand/or retrieval loop includes a first wire loop substantiallytraversing the first circumference formed from one of the stent wiresand a second wire loop partially traversing the first circumferenceformed from another of the stent wires, wherein the circumferentialportion of the second wire loop is juxtaposingly disposed to a portionof the circumferential portion of the first wire loop. The first wire atthe circumferential portion of the first wire loop may cross over thesecond wire at the circumferential portion of the second wire loop. Thefirst wire at the circumferential portion of the first wire loop may beattached to the second wire at the circumferential portion of the secondwire loop.

Desirably, the wires include biocompatible metallic and/or polymericmaterials. Useful materials include nitinol, cobalt-based alloy,stainless steel, platinum, gold, titanium, tantalum, niobium, polymericand combinations thereof. Desirably, the wires include nitinol. Thewires may be composite wires for improved radiopacity. Such compositewires may have an inner core of tantalum, gold, platinum, iridium orcombination of thereof and an outer portion of nitinol.

In another aspect of the present invention, a braided stent having anintegral repositioning and/or retrieval loop is provided. The braidedstent includes a plurality of wires having first and second endsinterbraided in a braided pattern to form a tubular stent having opposedatraumatic first and second open ends with each open end having acircumference; wherein the first and second wires ends are disposed atthe second stent open end and the wires are looped at the second stentopen end so that none of the first or second wires ends are exposed atthe circumference of second stent open end; wherein at least of two ofthe wires are formed into a repositioning and/or retrieval loop havingan elongated portion circumferentially disposed at the first opposedopen end; and wherein the reposition and/or retrieval loop includes twosections which run adjacent to each other prior to crossing to permitgrabbing of both sections simultaneously by a practitioner. The firstsection of the reposition and/or retrieval loop may include a first wireloop substantially traversing the first circumference formed from one ofthe stent wires; and the second section of the reposition and/orretrieval loop may include a second wire loop partially traversing thefirst circumference formed from another of the stent wires, wherein thecircumferential portion of the second wire loop is juxtaposinglydisposed to a portion of the circumferential portion of the first wireloop. Desirably, the second wire loop includes two legs longitudinallyextending from the interbraided portion of the stent. The legs mayinclude a base and an apex, wherein the base is integral with theinterbraided portion of the stent and where the wire is angularly bentat the apices to form the circumferential portion of the second wireloop.

Desirably, the first wire at the circumferential portion of the firstwire loop crosses over the second wire at the circumferential portion ofthe second wire loop. The first wire at the circumferential portion ofthe first wire loop may also be attached to the second wire at thecircumferential portion of the second wire loop.

Except for the second wire, the wires at the first stent end may have anangular bend defining the initial portion of the braided pattern. Thefirst wire at the circumferential portion of the first wire loop maycross over at least one of the angular bends at the first stent end orthe first wire at the circumferential portion of the first wire loop maybe attached to at least one of the angular bends at the first stent end.

The wires may be made from biocompatible metallic and/or polymericmaterials. Desirably, the wire materials are selected from the groupconsisting of nitinol, cobalt-based alloy, stainless steel, platinum,gold, titanium, tantalum, niobium, polymeric and combinations thereof.Desirably, the wires include nitinol. The wires may be composite wiresfor improved radiopacity. The composite wires may have an inner core oftantalum, gold, platinum, iridium or combination of thereof and an outerportion of nitinol.

Desirably, the stent includes an even number of wires from about 10 toabout 36.

The stent may frrther include a hollow tubular covering disposed overthe interior or the exterior surface. The tubular covering may be anuninterrupted covering. The tubular covering may substantially cover thestent. The tubular covering may partially cover portions of the stent.Desirably, the tubular covering substantially covers the stent,excluding portions of the repositioning and/or retrieval loop.Desirably, the covering is a polymeric material. Useful polymericmaterials may include polyester, polypropylene, polyethylene,polyurethane, polynaphthalene, polytetrafluoroethylene, expandedpolytetrafluoroethylene, silicone, and combinations thereof.

In another aspect of the present invention, a method for producing atubular braided stent having opposed first and second stent ends andhaving an integral repositioning and/or retrieval loop at the firststent end is provided. The method includes the steps of selecting aplurality of elongate biocompatible wires having opposed ends; forming areposition and/or retrieval loop from two of the wires including twosections which run adjacent to each other prior to crossing to permitgrabbing of both sections simultaneously by a practitioner; and braidingthe wires to form the stent. The step for forming the reposition and/orretrieval loop may further include forming a first section bycircumferentially disposing one wire prior to braiding. The step forforming the reposition and/or retrieval loop may further include forminga second section by circumferentially disposing a second wire andangularly bending the second wire to form two longitudinally legs priorto braiding. The step of braiding the wires may further include braidingthe wires such that the opposed wires ends terminate at the second endof the stent. The method may firther include bending the wires at thesecond end to form wire loops thereat. The method may flurther includewelding the wire ends to form closed wire loops thereat. Desirably, thewire ends are welded proximal to a portion of the closed wire loops. Thewire ends may be welded at a braided wire portion located proximally,but before, the closed wire loop ends.

Desirably, the step of selecting wires further includes selecting aneven number of wires. The even number of wires may be from about 10 toabout 36.

Desirably, the wires at the first end of the stent are angularly bentprior to the step of braiding so that no wire ends are disposed at thefirst end of the stent. The wires at the first end of the stent may beangularly bent to form wire bends prior to the step of braiding so thatno wire ends are disposed at the first end of the stent, and furtherwherein the one wire forming the first section crosses over at least oneof the wire bends.

In another aspect of the present invention, a method of repositioningand/or retrieving an implantable stent is provided. The method includesthe steps of providing a stent, which includes a plurality of wireshaving first and second ends interbraided in a braided pattern to form atubular stent having opposed atraumatic first and second open ends witheach open end having a circumference; wherein the first and second wiresends are disposed at the second stent open end and the wires are loopedat the second stent open end so that none of the first or second wiresends are exposed at the circumference of second stent open end; whereinat least of two of the wires are formed into a repositioning and/orretrieval loop having an elongated portion circumferentially disposed atthe first opposed open end; and wherein the reposition and/or retrievalloop includes two sections which run adjacent to each other prior tocrossing; and grabbing of both sections the reposition and/or retrievalloop simultaneously to reposition and/or retrieve the stent. Desirably,the step of grabbing further includes using forceps to both sections thereposition and/or retrieval loop.

In another aspect of the present invention, use of an implantable stenthaving a repositioning and/or retrieving loop is provided. Desirably, inuse the stent includes a plurality of wires having first and second endsinterbraided in a braided pattern to form a tubular stent having opposedatraumatic first and second open ends with each open end having acircumference; wherein the first and second wires ends are disposed atthe second stent open end and the wires are looped at the second stentopen end so that none of the first or second wires ends are exposed atthe circumference of second stent open end; wherein at least of two ofthe wires are formed into a repositioning and/or retrieval loop havingan elongated portion circumferentially disposed at the first opposedopen end; and wherein the reposition and/or retrieval loop includes twosections which run adjacent to each other prior to crossing; whereinboth sections the reposition and/or retrieval loop may be simultaneouslyaccessed or grabbed to reposition and/or retrieve the stent. Desirably,the accessing or grabbing of the both sections further includes use offorceps to both sections the reposition and/or retrieval loop.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a hollow, tubular stent according to thepresent invention.

FIG. 2 is an expanded view of a wall portion of the stent of FIG. 1taken along the 2-2 axis showing a plurality of stent wires.

FIG. 3 depicts a braided stent with a closed-end loop design havingatraumatic stent ends with no loose wires ends thereat.

FIG. 4 is a perspective view on one end of the stent of FIG. 3 having aretrieval and/or repositioning loop according to the present invention.

FIG. 5 is a front perspective view of the retrieval and/or repositioningloop of FIG. 4 according to the present invention.

FIG. 6 is a side perspective view of the retrieval and/or repositioningloop of FIG. 4 according to the present invention.

FIG. 7 is a back perspective view of the retrieval and/or repositioningloop of FIG. 4 according to the present invention.

FIG. 8 is an expanded view of the retrieval and/or repositioning loop ofFIG. 5 according to the present invention.

FIG. 9 is an expanded view of the retrieval and/or repositioning loop ofFIG. 7 according to the present invention.

FIG. 10 is an expanded view of the retrieval and/or repositioning loopof FIG. 6 according to the present invention.

FIG. 11A is another view of the retrieval and/or repositioning loop ofFIG. 4 according to the present invention.

FIG. 11B is a view of the stent of FIG. 11 in a retracted or compressedstate according to the present invention.

FIG. 12 is a perspective view of a mandrel useful for forming theretrieval and/or repositioning loop of FIG. 4 according to the presentinvention.

FIG. 13 is a flat schematic of the mandrel of FIG. 12 showing pin andwire details.

FIG. 14 is an expanded view of a grabbing or access area of theretrieval and/or repositioning loop of FIG. 4 according to the presentinvention.

FIG. 15 is a top schematic view of a circumferential wire forming theretrieval and/or repositioning loop of FIG. 4 according to the presentinvention.

FIG. 16 is a depiction of a stent having an embodiment of the retrievaland/or repositioning loop according to the present invention.

FIG. 17 is a depiction of a stent having another embodiment of theretrieval and/or repositioning loop according to the present inventionand further having a polymeric coating.

FIG. 18 is a schematic depiction for a technique for providing thepolymeric coating on the stent according to the present invention.

FIG. 19A is a schematic depiction for offset welding of stent wire endsaccording to the present invention.

FIG. 19B is a view of the stent of FIG. 19A having the offset weldsaccording to the present invention.

FIG. 20 depicts a stent having a covering of silicone according to thepresent invention.

FIG. 21 is a cross-section view of the stent of FIG. 20 showing an outercovering of silicone about the stent according to the present invention.

FIG. 22 is a cross-section view of the stent of FIG. 20 showing an innercovering of silicone about the stent according to the present invention.

FIG. 23 is another expanded view of the retrieval and/or repositioningloop of FIG. 4 according to the present invention.

FIG. 24 is another expanded view of the retrieval and/or repositioningloop of FIG. 4 according to the present invention.

FIG. 25 is another expanded view of the retrieval and/or repositioningloop of FIG. 4 according to the present invention.

DETAILED DESCRIPTION

The present invention provides at least one retrieval and/orrepositioning loop (RRL) which is integral and formed from one of thewires which are braided to form the stent. The retrieval and/orrepositioning loop retrieval and/or repositioning loop is designed toprovide a structure which has the required tensile strength to preventfracture or damage to the stent when force is applied to reposition orretrieve the stent, yet allows for a very low delivery profile such thatit can easily be loaded onto a delivery device without interfering withthe deployment into the body or requiring increased deployment force.Since the retrieval and/or repositioning loop retrieval and/orrepositioning loop is part of the actual braided stent structure per se,as opposed to being a separate add-on element, no joining, i.e.,welding, crimping or twisting, of the retrieval and/or repositioningloop retrieval and/or repositioning loop to the braided stent structureis necessary. Tensile strength of the retrieval and/or repositioningloop may thus be maximized while concomitantly maintaining the lowestprofile for delivery to a patient. The wire or wires used to form atleast one retrieval and/or repositioning loop may be of the same typeand material as the other wires forming the braided stent, oralternatively they may be made from different types or materials. In onedesirable embodiment, the retrieval and/or repositioning loop is madefrom wire which is the same material and diameter, i.e., outsidediameter (OD), as other wires which form the braided stent. In thismanner, the retrieval and/or repositioning loop can further seamlesslytransition into the body of the stent. As used herein, the phrase“retrieval and/or repositioning loop” refers to a retrieval loop, arepositioning loop, or a combination thereof which is integrally formedwith a stent and, when a longitudinally pulling force is appliedthereto, aids in the radial contraction or cinching of the stent tofacilitate movement, repositioning and/or retrieval of the stent.

More than one retrieval and/or repositioning loop may be incorporatedinto the stent. For example, each stent end might have one or moreretrieval and/or repositioning loops. In some embodiments only oneretrieval and/or repositioning loop is present at one or more ends.

FIG. 1 depicts stent 10 of the present invention. Stent 10 is a hollowtubular structure having opposed first and second open ends 12, 14 andhaving a tubular wall 16 therebetween. A portion of the tubular wall 16is depicted in FIG. 2 as having a plurality of elongate wires 18 formedinto the tubular wall 16. The elongate wires 18 traverse the length ofthe stent 10 in a direction traverse to the longitudinal length of thestent 10. The elongate wires 18 may be formed into the tubular wall 16by braiding the wires 18, winding the wires 18, knitting the wires 18,and combinations thereof. Preferably, the wires 18 are braided in abraided pattern 20 to form the tubular wall 16. A useful nonlimitingbraided pattern includes a one over and one under pattern, but otherpatterns may suitably be used.

As depicted in FIG. 3, stent 10 is desirably an atraumatic stent havingno sharp terminating members at one or both of the opposed first andsecond open ends 12, 14. The elongate wires 18 terminating at open end12 are mated to form closed loops 22 and adjacently mated wires aresecured to one and the other by mechanical means, such as welds 26. Thepositioning of adjacently mated wires to form closed-loop end designs isfurther described in U.S. Published application No. US 2005-0049682 A1,and U.S. Provisional Application No. 60/680,630, titled “AtraumaticStent With Reduced Deployment Force, Method For Making The Same AndMethod And Apparatus For Deploying And Positioning The Stent”, filed onMay 13, 2005, which was filed as U.S. patent application Ser. No.11/271,774 on Nov. 10, 2005, the contents of all which are incorporatedherein by reference. Desirably, the elongate wires 18 terminating atopen end 12 are in a cathedral type arch or loop configuration. Furtherdetails of the cathedral type of arch or closed-loop configuration maybe found in U.S. application Ser. No. 10/845,844, filed May 15, 2004,the contents of which are incorporated herein by reference.

The stent wires 18 at the open end 14 are bent to form closed loop ends24 thereat. As depicted in FIG. 3, the loop ends 24 are substantiallyangular having approximately or about a 90° bend. The radius ofcurvature at the point of the bend is desirably minimized. In otherwords, the loop ends 24 desirably have an angularly bent portion betweensubstantially straight wire portions that do not otherwise have aportion with a significant radius of curvature. The loop ends 24,however, are not limited to angular bends of 90° and other bend anglesmay suitably be used. For example, angular bends with a bend angle fromabout 30° to about 150° are also useful. Other useful bend anglesinclude from about 60° to about 120°, from about 70° to about 110°, fromabout 80° to about 100°, from about 85° to about 95°, and the like.

The stent 10 depicted in FIG. 3 includes multiple wires, such as 24wires 18 as depicted in FIG. 3, of nitinol or nitinol-containingmaterial. The wires are relatively thin at a diameter of about 0.011inches. The number of wires and the diameters of the wires, which may bethe same or different, depicted in FIG. 3 are not limiting, and othernumbers of wires and other wire diameters may suitably be used.Desirably, an even number of wires are used, for example from about 10to about 36 wires.

Desirably, the wires 18 are made from any suitable implantable material,including without limitation nitinol, stainless steel, cobalt-basedalloy such as Elgiloy®, platinum, gold, titanium, tantalum, niobium,polymeric materials and combinations thereof. Useful and nonlimitingexamples of polymeric stent materials include poly(L-lactide) (PLLA),poly(D,L-lactide) (PLA), poly(glycolide) (PGA),poly(L-lactide-co-D,L-lactide) (PLLA/PLA), poly(L-lactide-co-glycolide)(PLLA/PGA), poly(D,L-lactide-co-glycolide) (PLA/PGA),poly(glycolide-co-trimethylene carbonate) (PGA/PTMC), polydioxanone(PDS), Polycaprolactone (PCL), polyhydroxybutyrate (PHBT),poly(phosphazene) poly(D,L-lactide-co-caprolactone) PLA/PCL),poly(glycolide-co-caprolactone) (PGA/PCL), poly(phosphate ester) and thelike. Wires made from polymeric materials may be also include radiopaquematerials, such as metallic-based powders, particulates or pastes whichmay be incorporated into the polymeric material. For example theradiopaque material may be blended with the polymer composition fromwhich the polymeric wire is formed, and subsequently fashioned into thestent as described herein. Alternatively, the radiopaque material may beapplied to the surface of the metal or polymer stent. In eitherembodiment, various radiopaque materials and their salts and derivativesmay be used including, without limitation, bismuth, barium and its saltssuch as barium sulphate, tantulaum, tungsten, gold, platinum andtitanium, to name a few. Additional useful radiopaque materials may befound in U.S. Pat. No. 6,626,936, which is herein incorporated in itsentirely by reference. Metallic complexes useful as radiopaque materialsare also contemplated. The stent may be selectively made radiopaque atdesired areas along the wire or made be fully radiopaque, depending onthe desired end-product and application. Further, the wires 18 have aninner core of tantalum, gold, platinum, iridium or combination ofthereof and an outer member or layer of nitinol to provide a compositewire for improved radiocapicity or visibility. Desirably, the inner coreis platinum and the outer layer is nitinol. More desirably, the innercore of platinum represents about at least 10% of the wire based on theoverall cross-sectional percentage. Moreover, nitinol that has not beentreated for shape memory such as by heating, shaping and cooling thenitinol at its martensitic and austenitic phases, is also useful as theouter layer. Further details of such composite wires may be found inU.S. Patent Application Publication 2002/0035396 A1, the contents ofwhich is incorporated herein by reference. Preferably, the wires 18 aremade from nitinol, or a composite wire having a central core of platinumand an outer layer of nitinol. Further, the filling weld material, ifrequired by welding processes such as MIG, may also be made fromnitinol, stainless steel, cobalt-based alloy such as Elgiloy, platinum,gold, titanium, tantalum, niobium, and combinations thereof, preferablynitinol. The material of the cathode is no critical and can be made outof any suitable metal. The filling weld material and the wire 18 may bemade of the same material, for example nitinol.

Further, the wires 18 may have a composite construction, such asdescribed found in U.S. Patent Application Publication 2002/0035396 A1,the contents of which is incorporated herein by reference. For example,the wires 18 may have an inner core of tantalum gold, platinum, iridiumor combination of thereof and an outer member or layer of nitinol toprovide a composite wire for improved radiocapicity or visibility.Preferably, the wires 18 are made from nitinol.

Either of both of the opposed open ends 12, 14 of the stent 10 may havea retrieval and/or repositioning loop thereat. The retrieval and/orrepositioning loop is useful for repositioning and/or retrieval of animplanted or deployed stent 10. The retrieval and/or repositioning loopallows a practitioner to contract and move, reposition and/or retrievethe stent 10 within an implanted lumen (not shown). The stent retrievalmember may be made from a memory shape alloy, such as the abovedescribed materials, including nitinol. The use of a shape memorymaterial, as compared other convention materials such as suture thread,has numerous advantages. For example, the self-supporting nature of theshape memory material facilitates the locating of the retrieval and/orrepositioning loop. A memory shape alloy member will not tangle, apotential problem with suture loops, especially with suture loops madefrom natural or polymeric threads or filaments, and will also aid inopening the stent 10. Another advantage from using a memory shape alloymaterial is the wire loop defining the retrieval and/or repositioningloop would be less likely to break than a plastic or polymeric loop whena pulling force is applied, such as required for repositioning orremoval of the stent 10.

As depicted in FIG. 4 the stent 10 includes the retrieval and/orrepositioning loop 28. The retrieval and/or repositioning loop 28includes a first section 30 having a stent wire 32 that is substantiallycircumferentially disposed the end 14 of stent 10. The retrieval and/orrepositioning loop 28 includes a second section 34 having acircumferential portion that only partially traverses the circumferenceof the end 14 of stent 10. The retrieval and/or repositioning loopsecond section 34 includes two legs 36, 38 that emerge from the braid 20of the stent 10. In other words, the base 40 of the legs 36, 38 arecontained within the braided pattern 20 of the stent 10. The wire 32forming the first section 30 of the retrieval and/or repositioning loop28 is also desirably part of the braid pattern 20 of the stent 10. Inother words, the wire 32, after forming the first section 30 of theretrieval and/or repositioning loop 28, enters into the normal braidingpattern 20 of the stent 10. The apex 42 of the legs 36, 38 is angularlybent thereby forming a top portion 44 having a length that partiallycircumvents the circumference of the stent end 14. The top portion 44 isprovided with a circumferential length to permit easy access by apractitioner of the retrieval and/or repositioning loop 28. When thefirst section 30 and the second section 34 of the retrieval and/orrepositioning loop 28 are accessed and pulled, such as by portion 46 ofthe retrieval and/or repositioning loop 28 where in first section 30 andthe second section 34 are juxtaposingly disposed to one and another, thestent end 14 is axially compressed or radially contracted by a cinchingaction of the circumferential portion of the wire 32. Such a portion 34may also be referred to as a grabbing area or portion 34 as it isconfigured for easy access by a practitioner, for example a practitionerusing forceps (not shown). Further, as wires forming both the first andsection sections 30, 34 are integral with the braid pattern 20 of thestent 10, such integral wires further facilitate movement, repositioningor retrieval of the stent 10 by, among other things, providing acinching or radially contracting action along the longitudinal length ofthe stent and also by transferring the pulling force along thelongitudinal length of the stent. Thus, the pulling of the retrievaland/or repositioning loop 28 provides for simultaneous contracting andpulling of the stent 10. In contrast, if a pulling force is applied toan end of a stent without having a retrieval and/or repositioning loop28, there is no cinching or radial contracting force generated at thatstent end. For example, assuming there is not retrieval and/orrepositioning loop 28 integrally formed and disposed at the stent end12, when a practitioner pulls on the closed loops 22 of stent end 12 togenerate a pulling force thereat, a cinching or radial contracting forceis not generated at that end 12 of the stent 10. In a similar manner,assuming there is not retrieval and/or repositioning loop 28 integrallyformed and disposed at the stent end 14, when a practitioner pulls onthe loop ends 24 of stent end 14 to generate a pulling force thereat, acinching or radial contracting force is not generated at that end 14 ofthe stent 10.

FIG. 5 depicts a partial front view of the stent 10 having the retrievaland/or repositioning loop 28 of the present invention. The stent wires18 on the front face of the stent 10 are depicted, but the stent wires18 on the back face are not shown for simplicity and for betterillustration of the retrieval and/or repositioning loop 28 of thepresent invention. The. FIG. 6 depicts a side view of the stent 10having the retrieval and/or repositioning loop 28. FIG. 7 depicts a backview of the stent 10 having the retrieval and/or repositioning loop 28.As depicted in FIGS. 5-7 the retrieval and/or repositioning loop 28desirably extends longitudinally outward from the braided portionsforming the remaining portion of the stent end 14. Such extended andelongated retrieval and/or repositioning loop 100 facilitates grabbingof the retrieval and/or repositioning loop 100 by a practitioner.

As depicted in FIG. 8, the wire 32 forming the first section 102 of theretrieval and/or repositioning loop 100 may cross over the wire the wireforming the second section 104. This advantageously permits apractitioner to grab both section 30 of the retrieval and/orrepositioning loop 28 advantageously circumscribes the circumferentialperimeter of the end 14 of the stent 10. Such a encompassing of thecircumferential perimeter of the stent end 14 facilitates access by apractitioner and also facilitates in a cinching action of the stent end14 when a longitudinal pulling force is applied to the retrieval and/orrepositioning loop 28 of the present invention. The present invention,however, is not limited to a wire, for example wire 32, or a firstsection 30 which completely circumscribes the circumferential perimeterof the stent end 14. For example, wire 32 or the first section 30 maysuitably substantially circumscribe the circumferential perimeter of thestent end 14 or may suitably partially circumscribe the circumferentialperimeter of the stent end 14.

FIG. 6 depicts a partial side view of the stent 10 having the retrievaland/or repositioning loop 28 of the present invention. The stent wires18 on the front side face of the stent 10 are depicted, but the stentwires 18 on the back side face are not shown for simplicity and forbetter illustration of the retrieval and/or repositioning loop 28 of thepresent invention. As depicted in FIG. 6, the wire 30 extendslongitudinally away or outward from the stent end 14 so that it isjuxtaposingly disposed with the second section 34 at the grabbing area46. Such a longitudinal extent facilitates access to the retrievaland/or repositioning loop 28 of the present invention by, for example, apractitioner.

FIG. 7 depicts a partial back view of the stent 10 having the retrievaland/or repositioning loop 28. The stent wires 18 on the back face of thestent 10 are depicted, but the stent wires 18 on the front face are notshown for simplicity and for better illustration of the retrieval and/orrepositioning loop 28 of the present invention. The stent wires 18 onthe front side face of the stent 10 are depicted, but the stent wires 18on the back side face are not shown for simplicity and for betterillustration. The second section 34 of the retrieval and/orrepositioning loop 28 has a shape of an inverted “U”, i.e., the top oflegs 36, 38 are unitary with the top portion 44 of the second section34, while the bottom of the legs 36, 38 are not interconnected so thatwhen grabbing area 46 or the top portion 44 is pulled the legs 36, 38may move toward one and another, thereby facilitating cinching or radialcontraction of the stent end 14 and of stent 10 of present invention. Asdepicted in FIGS. 5-7 the retrieval and/or repositioning loop 28desirably extends longitudinally outward from the braided portionsforming the remaining portion of the stent end 14. Such an extended andelongated retrieval and/or repositioning loop 28 facilitates grabbing ofthe retrieval and/or repositioning loop 28 by a practitioner.

FIG. 8 is an expanded partial view of the wires forming the retrievaland/or repositioning loop 28 of the present invention. The wire 32 offirst section 30 of the retrieval and/or repositioning loop 28 of thepresent invention may juxtaposingly cross over the wire 48 of the secondportion 34 at the top portion 44 of second section 34. The wires 32, 48may abuttingly and slidably engage one and the other in an unlocked orunsecured fashion to allow movement therebetween. Such a crossing of thewires 48 and 32 in a freely moving, juxtaposingly relationshipadvantageously permits a practitioner to grab both sections 30, 34 toretrieve or reposition the stent 10. The present invention, however, isnot so limited and the wires 32, 48 may be secured to one and the otherthereat by other means, for example suturing, welding and the like.

As depicted in FIGS. 9-10, the wire 32 forming the first section 30 ofthe retrieval and/or repositioning loop 28 may cross through some, butnot all, of the angular bends 24 at stent end 14. For example, some ofthe angular bends 24 may be longitudinally offset from other of theangular bends 24, and the wire 32 may suitably cross through those bends24 at the very end of the stent 10 while no crossing through the bends24 that are disposed inwardly from the stent end 14. As depicted in FIG.9, the angular bends 24 are longitudinally offset from one and theother, but the present invention is not so limited. For example, thestent 10 may have no offsetting of the bends 24 at stent end 14.Further, as depicted in FIG. 10, as indicated by wire portion 76, thewire 32 forming the first section 30 of the retrieval and/orrepositioning loop 28 may extend substantially about the circumferenceof the stent end 14, which is defined by the angular bends 24, and thenhave a longitudinal extent 50 jutting away from the stent end 14. Thetop portion 52 of the longitudinal extend 50 may then cross the topportion 44 of the second section 34 (not shown) of the retrieval and/orrepositioning loop 28. This aspect of the retrieval and/or repositioningloop 28 of the present invention differs from the aspect depicted inFIG. 6 where the wire 32 traverses from one or more angular bends 24 ina diagonal fashion toward the grabbing area 46 of the retrieval and/orrepositioning loop 28. The present invention, however, is not solimited, and the wire 32, i.e. the top portion 52, need not cross thegrabbing area 46 of the second section 34. In such an aspect or thepresent invention, the retrieval and/or repositioning loop 28 may beformed by the wire 32 and does not have to include the wire 48. In otherwords, the retrieval and/or repositioning loop 28 of the presentinvention may suitably be formed from only the first section 30 wherethe wire 32 extends substantially about the circumference of the stentend 14. In such an aspect of the present invention, the first section30, when pulled, provides a cinching or radial contraction action and alongitudinal stretching action for movement, repositioning or retrievalof the stent 10. Further, as depicted in FIG. 10, the top portion 52 ofthe retrieval and/or repositioning loop 28 may extend radially outwardfrom the stent end 14 to facilitate access by a practitioner. Thepresent invention, however, is not so limited, and the top portion 52 ofthe retrieval and/or repositioning loop 28 may extend slightly inwardlyin a radially fashion or be substantially longitudinally in line orparallel with the longitudinal wall of the stent 10. Such a radiallyinward, radially outwardly or radially parallel configuration may alsobe present in the grabbing area 46 having both the first and secondsections 30, 34 of the retrieval and/or repositioning loop 28 of thepresent invention.

As depicted in FIGS. 11-12, the stent 10 easily contracts uponapplication of a pulling force, “P”, to the retrieval and/orrepositioning loop 28.

Referring to FIGS. 12-13, the retrieval and/or repositioning loop 28 ofthe present invention may be formed by wrapping one wire, for examplewire 32, around template pins 56 disposed on a mandrel 54 prior tobraiding the stent 10 to form a perimetrical section 58 which isgenerally circular. Such a perimetrical section 58 desirably forms thefist section 30 of the retrieval and/or repositioning loop 28 of thepresent invention. The retrieval and/or repositioning loop 28 also thenmay be provided with a larger exaggerated section 60, such as grabbingarea 46, for easy grabbing by the practitioner or physician. Thisexaggerated section 60, 46 of the retrieval and/or repositioning loop 28is also formed by wrapping a second wire 48 around template pins 56positioned on the mandrel 54 to cause the desired looped shape. Apulling force on the retrieval and/or repositioning loop 28 will causecinching of the braid to a smaller diameter as it lengthens axial, bythus allowing for less frictional force against the vessel wall andpermitting repositioning and/or retrieval of the deployed stent. Theretrieval and/or repositioning loop wires are then braided in with theother wires, for example wires 18, using the braiding technique asdescribed herein.

The retrieval and/or repositioning loop may be interlaced with one ormore adjacent end loops formed from other wires as it is wrapped aroundthe mandrel, or it need not be interlaced with any adjacent wire loopsat the stent end. In the latter case, optional attachment methods suchas sutures or clamps may be used to attach the retrieval and/orrepositioning loop to one or more adjacent end loops of the stent.Having the retrieval and/or repositioning loop interlace with one ormore, and desirably at least two adjacent end loops from the otheradjacent wires is one particularly desirable embodiment.

In one particularly useful embodiment, the retrieval and/orrepositioning loop is designed to be grabbed at the area where the stentwires 30, 48 forming the retrieval and/or repositioning loop 28 crossesthemselves as shown in FIG. 8. The retrieval and/or repositioning loop28 may have an exaggerated loop or distended section 46, 60 where itcrosses itself and when grabbed at this crossing by the operator, theamount of distance the retrieval and/or repositioning loop will have tobe pulled will be reduced by about one-half. In other words, pulling theretrieval and/or repositioning loop at the crossing point of itself(double pull wire), reduces the length of the pulled retrieval and/orrepositioning loop by about one-half. As shown in FIG. 14, the grabbingarea 46 where the retrieval and/or repositioning loop wires 32, 48 crossmay be made to be as large as possible to facilitate and ensure the twosections of the retrieval and/or repositioning loop wire can be grabbedtogether. This may allow for enhanced endoscopic visualization of thestent. The grabbing area 46 is desirably sized for at least two of thewire crossings in the braid pattern of the stent.

The grabbing area of the retrieval and/or repositioning loop can bepositioned at any desired location along the wire from which it isformed prior to the wire crossing adjacent wires to begin the braid. Insuch cases the retrieval and/or repositioning loop may be a single pullwire and the pull length may be longer (approximately twice the length)than the pull length of those designed to be pulled at the section wherethe retrieval and/or repositioning loop crosses itself.

The retrieval and/or repositioning loop may also have the same ordifferent properties than other wires which form the braided stent. Forexample, it may be of the same or different stiffness or flexibility,all of which may be tailored for a particular application. The choice ofmaterial, wire diameter and pre-treatment of the wires and stentconfiguration are some of the factors which may be varied to achieveparticular stent properties. Additionally, as mentioned herein, the atleast one retrieval and/or repositioning loop may also be maderadiopaque by various methods, for example with a coating or finish,with a band or as part of the stent material, as further describedherein. Color or different finishes may also be added to the retrievaland/or repositioning loop to visually differentiate it from the rest ofthe stent wires.

As depicted in FIG. 14, the grabbing area 46 includes two juxtaposedwires 32, 148. The grabbing area 46, however, is not so limited. Asdepicted in FIG. 15, the retrieval and/or repositioning loop 28′ mayinclude only the circumferential wire 32 that is subsequentlyinterbraided to form the stent 10. Further as depicted in FIG. 15, thecircumferential wire 32, whether forming the retrieval and/orrepositioning loop 28′ by itself or forming the retrieval and/orrepositioning loop 28 in conjunction with another stent wire 48, isdesirably part of the braided wires 18 used in forming the stent 10,thereby forming the integral retrieval and/or repositioning loop 28 ofthe present invention. The stent 10 may then be braided to form atubular structure. Stent wires 18 are disposed about pins 62 and afterwhich braiding of the wires commence. Additional details of braiding maybe found in U.S. Pat. No. 6,792,979, the contents of which areincorporated herein by reference.

As depicted in FIGS. 16-17, the stent 10 of the present invention mayhave the integral retrieval and/or repositioning loop 28, 28′ integrallyformed at either stent 12, 14.

Further the stent 10 of the present invention may have a coating.Desirably, the coating is a tubular covering of silicone. As depicted inFIG. 18, the stent 10 may be placed on a coating mandrel (not shown) bymeans of a tie 64 after which the assembly is dipped into a siliconesolution to form the coating. Desirably, the retrieval and/orrepositioning loop portion 28 is not silicone covered. Desirably thecoating or covering is a silicone covering, but other coverings,particularly elastomeric polymers, are useful. The coating embeds thestent 10 therein and essentially forms a stent covering. When coating,it is desirable not to embed the retrieval and/or repositioning loopsection 28, 28′ in the covering, although the other wire portionsemanating from the retrieval and/or repositioning loop 28, 28′ whichform the braid of the stent may be coated. To prevent coating of theretrieval and/or repositioning loop section, the mandrel may betruncated or geometrically altered such that it does not permit coatingof the retrieval and/or repositioning loop, or the retrieval and/orrepositioning loop can be pulled away from the mandrel during coatingand formation of the polymer covering.

In one embodiment of the present invention, one end of the stent 10 mayhave weld joints 68 which, due to their positioning, provide higherradial strength, i.e., the resultant stents 10 can withstand higherradial compressive forces without fear of weld failure. In theseembodiments, the weld joint 68 is positioned between the crossings ofadjacent wires, as shown in FIGS. 19A and 19B. As depicted in FIG. 19A,wires 18 to be welded may be disposed about islands or pins 66 on amandrel (not shown). After the welds 68 are formed or while the welds 68are being formed wire portions not forming the stent 10 may be cut orotherwise removed from the stent braiding pattern 20.

As depicted in FIG. 20, the stent 10 may be fully, substantially orpartially covered or lined with a polymeric material.70. The stent 10may also be embedded in a polymeric coating. The covering may be in theform of a tubular structure. Nonlirniting examples of useful polymericmaterials include polyesters, polypropylenes, polyethylenes,polyurethanes, polynaphthalenes, polytetrafluoroethylenes, expandedpolytetrafluoroethylene, silicone, and combinations and copolymersthereof. Desirably, the polymeric material 70 is silicone. The polymericmaterial and/or silicone 70 may be disposed on external surfaces 72 ofthe stent 10, as depicted in FIG. 21, or disposed on the internalsurfaces 74 of the stent 10, as depicted in FIG. 22, or combinationsthereof.

FIGS. 23-25 depict additional details of the stent end 14 having theretrieval and/or repositioning loop 28. As depicted in FIGS. 23-25,which are partial schematic views showing generally only front facewires 18 in the braid pattern 20, the wire 32 may have a substantiallyor partially extending circumferential portion 76 and a longitudinallyextending portion 50 so that the sections 30 and 34 of the retrievaland/or repositioning loop 28 are juxtaposed or have portion that arejuxtaposed with one and the other, desirably in slidably relationshipwhich may also be an abutting relationship.

With any embodiment, the stent 10 may be used for a number of purposesincluding to maintain patency of a body lumen, vessel or conduit, suchas in the coronary or peripheral vasculature, esophagus, trachea,bronchi colon, biliary tract, urinary tract, prostate, brain, and thelike. The devices of the present invention may also be used to support aweakened body lumen or to provide a fluid-tight conduit for a bodylumen.

Also, the stent 10 may be treated with any known or useful bioactiveagent or drug including without limitation the following:anti-thrombogenic agents (such as heparin, heparin derivatives,urokinase, and PPack (dextrophenylalanine proline argininechloromethylketone); anti-proliferative agents (such as enoxaprin,angiopeptin, or monoclonal antibodies capable of blocking smooth musclecell proliferation, hirudin, and acetylsalicylic acid);anti-inflammatory agents (such as dexamethasone, prednisolone,corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine);antineoplastic/antiproliferative/anti-miotic agents (such as paclitaxel,5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones,endostatin, angiostatin and thymidine kinase inhibitors); anestheticagents (such as lidocaine, bupivacaine, and ropivacaine);anti-coagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGDpeptide-containing compound, heparin, antithrombin compounds, plateletreceptor antagonists, anti-thrombin antibodies, anti-platelet receptorantibodies, aspirin, prostaglandin inhibitors, platelet inhibitors andtick antiplatelet peptides); vascular cell growth promotors (such asgrowth factor inhibitors, growth factor receptor antagonists,transcriptional activators, and translational promotors); vascular cellgrowth inhibitors (such as growth factor inhibitors, growth factorreceptor antagonists, transcriptional repressors, translationalrepressors, replication inhibitors, inhibitory antibodies, antibodiesdirected against growth factors, bifunctional molecules consisting of agrowth factor and a cytotoxin, bifunctional molecules consisting of anantibody and a cytotoxin); cholesterol-lowering agents; vasodilatingagents; and agents which interfere with endogenous vascoactivemechanisms.

Further, with any embodiment of the stent 10 the general tubular shapemay be varied. For example, the tubular shape may have a varieddiameter, may be tapered, and may have an outwardly flared end and thelike. Further, the ends of the stent may have a larger diameter than themiddle regions of the stent. In one particularly useful embodiment, atleast one of the ends of the stent transition from one diameter toanother diameter. Desirably, both ends transition in this manner toyield “flared” ends, as depicted in FIG. 19.

The stent may be coated with a polymeric material. For example, thestent wires may be partially or fully covered with a biologically activematerial which is elutably disposed with the polymeric material.Further, the polymeric coating may extend over or through theinterstitial spaces between the stent wires so as to provide a hollowtubular liner or cover over the interior or the exterior surface of thestent. The polymeric material may be selected from the group consistingof polyester, polypropylene, polyethylene, polyurethane,polynaphthalene, polytetrafluoroethylene, expandedpolytetrafluoroethylene, silicone, and combinations thereof.

Various stent types and stent constructions may be employed in theinvention. Among the various stents useful include, without limitation,self-expanding stents and balloon expandable extents. The stents may becapable of radially contracting, as well and in this sense can best bedescribed as radially distensible or deformable. Self-expanding stentsinclude those that have a spring-like action which causes the stent toradially expand, or stents which expand due to the memory properties ofthe stent material for a particular configuration at a certaintemperature. Nitinol is one material which has the ability to performwell while both in spring-like mode, as well as in a memory mode basedon temperature. Other materials are of course contemplated, such asstainless steel, platinum, gold, titanium and other biocompatiblemetals, as well as polymeric stents. The configuration of the stent mayalso be chosen from a host of geometries. For example, wire stents canbe fastened into a continuous helical pattern, with or without awave-like or zig-zag in the wire, to form a radially deformable stent.Individual rings or circular members can be linked together such as bystruts, sutures, welding or interlacing or locking of the rings to forma tubular stent. Tubular stents useful in the present invention alsoinclude those formed by etching or cutting a pattern from a tube. Suchstents are often referred to as slotted stents. Furthermore, stents maybe formed by etching a pattern into a material or mold and depositingstent material in the pattern, such as by chemical vapor deposition orthe like. Examples of various stent configurations are shown in U.S.Pat. No. 4,503,569 to Dotter; U.S. Pat. No. 4,733,665 to Palmaz; U.S.Pat. No. 4,856,561 to Hillstead; U.S. Pat. No. 4,580,568 to Gianturco;U.S. Pat. No. 4,732,152 to Wallsten, U.S. Pat. No. 4,886,062 to Wiktor,and U.S. Pat. No. 5,876,448 to Thompson, all of whose contents areincorporated herein by reference.

The invention being thus described, it will now be evident to thoseskilled in the art that the same may be varied in many ways. Suchvariations are not to be regarded as a departure from the spirit andscope of the invention and all such modifications are intended to beincluded within the scope of the following claims. Further, any of theembodiments or aspects of the invention as described in the claims maybe used with one and another without limitation.

1. A stent comprising: at least two elongate wires interlooped to form atubular stent having opposed first and second open ends with each openend having a circumference, wherein one of said at least two wires isformed into a repositioning and/or retrieval loop having an elongatedportion circumferentially disposed at said first opposed open end. 2.The stent of claim 1, wherein said at least interlooped two wires arebraided.
 3. The stent of claim 1, wherein said elongated circumferentialportion of said reposition and/or retrieval loop comprises a wire loopsubstantially traversing said first circumference.
 4. The stent of claim1, wherein said elongated circumferential portion of said repositionand/or retrieval loop comprises a wire loop partially traversing saidfirst circumference.
 5. The stent of claim 1, wherein said elongatedcircumferential portion of said reposition and/or retrieval loopcomprises a first wire loop substantially traversing said firstcircumference formed from one of said stent wires and a second wire looppartially traversing said first circumference formed from another ofsaid stent wires, wherein the circumferential portion of said secondwire loop is juxtaposingly disposed to a portion of the circumferentialportion of said first wire loop.
 6. The stent of claim 5, wherein saidfirst wire at said circumferential portion of said first wire loopcrosses over said second wire at said circumferential portion of saidsecond wire loop.
 7. The stent of claim 5, wherein said first wire atsaid circumferential portion of said first wire loop is attached to saidsecond wire at said circumferential portion of said second wire loop. 8.The stent of claim 1, wherein the wires comprise biocompatible metallicand/or polymeric materials.
 9. The stent of claim 8, wherein saidmetallic materials are selected from the group consisting of nitinol,cobalt-based alloy, stainless steel, platinum, gold, titanium, tantalum,niobium, polymeric and combinations thereof.
 10. The stent of claim 9,wherein said wires comprise nitinol.
 11. The stent of claim 8, whereinsaid wires are composite wires for improved radiopacity.
 12. The stentof claim 11, wherein said wires have an inner core of tantalum, gold,platinum, iridium or combination of thereof and an outer portion ofnitinol.
 13. A braided stent comprising: a plurality of wires havingfirst and second ends interbraided in a braided pattern to form atubular stent having opposed atraumatic first and second open ends witheach open end having a circumference; wherein said first and secondwires ends are disposed at said second stent open end and said wires arelooped at said second stent open end so that none of the first or secondwires ends are exposed at the circumference of second stent open end;wherein at least of two of said wires are formed into a repositioningand/or retrieval loop having an elongated portion circumferentiallydisposed at said first opposed open end; and wherein said repositionand/or retrieval loop comprises two sections which run adjacent to eachother prior to crossing to permit grabbing of both sectionssimultaneously by a practitioner.
 14. The stent of claim 13, whereinsaid first section of said reposition and/or retrieval loop comprises afirst wire loop substantially traversing said first circumference formedfrom one of said stent wires; and said second section of said repositionand/or retrieval loop comprises a second wire loop partially traversingsaid first circumference formed from another of said stent wires,wherein the circumferential portion of said second wire loop isjuxtaposingly disposed to a portion of the circumferential portion ofsaid first wire loop.
 15. The stent of claim 14, wherein said secondwire loop comprises two legs longitudinally extending from theinterbraided portion of said stent.
 16. The stent of claim 15, whereinsaid legs have a base and an apex, wherein said base is integral withthe interbraided portion of said stent and where said wire is angularlybent at said apices to form said circumferential portion of said secondwire loop.
 17. The stent of claim 14, wherein said first wire at saidcircumferential portion of said first wire loop crosses over said secondwire at said circumferential portion of said second wire loop.
 18. Thestent of claim 14, wherein said first wire at said circumferentialportion of said first wire loop is attached to said second wire at saidcircumferential portion of said second wire loop.
 19. The stent of claim13, wherein the wires comprise biocompatible metallic and/or polymericmaterials.
 20. The stent of claim 13, wherein, except for said secondwire, the wires at said first stent end have an angular bend definingthe initial portion of the braided pattern.
 21. The stent of claim 20,wherein said first wire at said circumferential portion of said firstwire loop crosses over at least one of the angular bends at said firststent end.
 22. The stent of claim 20, wherein said first wire at saidcircumferential portion of said first wire loop is attached to at leastone of the angular bends at said first stent end.
 23. The stent of claim13, wherein said metallic materials are selected from the groupconsisting of nitinol, cobalt-based alloy, stainless steel, platinum,gold, titanium, tantalum, niobium, polymeric and combinations thereof.24. The stent of claim 23, wherein said wires comprise nitinol.
 25. Thestent of claim 13, wherein said wires are composite wires for improvedradiopacity.
 26. The stent of claim 25, wherein said wires have an innercore of tantalum, gold, platinum, iridium or combination of thereof andan outer portion of nitinol.
 27. The stent of claim 13, wherein saidstent comprises an even number of wires from about 10 to about
 36. 28.The stent of claim 13, fturther comprising a hollow tubular coveringdisposed over the interior or the exterior surface.
 29. The stent ofclaim 28, wherein the tubular covering is an uninterrupted covering. 30.The stent of claim 28, wherein the tubular covering substantially coverssaid stent.
 31. The stent of claim 28, wherein the tubular coveringpartially covers portions of said stent.
 32. The stent of claim 28,wherein the tubular covering substantially covers said stent, excludingportions of the repositioning and/or retrieval loop.
 33. The stent ofclaim 28, wherein the covering is a polymeric material.
 34. The stent ofclaim 33, wherein the polymeric material is selected from the groupconsisting of polyester, polypropylene, polyethylene, polyurethane,polynaphthalene, polytetrafluoroethylene, expandedpolytetrafluoroethylene, silicone, and combinations thereof.
 35. Amethod for producing a tubular braided stent having opposed first andsecond stent ends and having an integral repositioning and/or retrievalloop at the first stent end, comprising: selecting a plurality ofelongate biocompatible wires having opposed ends; forming a repositionand/or retrieval loop from two of said wires comprising two sectionswhich run adjacent to each other prior to crossing to permit grabbing ofboth sections simultaneously by a practitioner; and braiding said wiresto form said stent.
 36. The method of claim 35, wherein the step forforming said reposition and/or retrieval loop further comprises forminga first section by circumferentially disposing one wire prior tobraiding.
 37. The method of claim 35, wherein the step for forming saidreposition and/or retrieval loop further comprises forming a secondsection by circumferentially disposing a second wire and angularlybending said second wire to form two longitudinally legs prior tobraiding.
 38. The method of claim 35, wherein the step of braiding saidwires further comprise braiding said wires such that said opposed wiresends terminate at the second end of the stent.
 39. The method of claim38, further comprising bending said wires at said second end to formwire loops thereat.
 40. The method of claim 39, further comprisingwelding said wire ends to form closed wire loops thereat.
 41. The methodof claim 40, wherein the wire ends are welded proximal to a portion ofthe closed wire loops.
 42. The method of claim 41, wherein the wire endsare welded braided wire portion located proximally, but before, saidclosed wire loop ends.
 43. The method of claim 35, wherein the step ofselecting wires further comprises selecting an even number of wires. 44.The method of claim 43, wherein the even number of wires is from about10 to about
 36. 45. The method of claim 35, wherein the wires at thefirst end of the stent are angularly bent prior to the step of braidingso that no wire ends are disposed at the first end of the stent.
 46. Themethod of claim 36, wherein the wires at the first end of the stent areangularly bent to form wire bends prior to the step of braiding so thatno wire ends are disposed at the first end of the stent, and furtherwherein said one wire forming said first section crosses over at leastone of said wire bends.
 47. A method of repositioning and/or retrievingan implantable stent, comprising: providing a stent comprising: aplurality of wires having first and second ends interbraided in abraided pattern to form a tubular stent having opposed atraumatic firstand second open ends with each open end having a circumference; whereinsaid first and second wires ends are disposed at said second stent openend and said wires are looped at said second stent open end so that noneof the first or second wires ends are exposed at the circumference ofsecond stent open end; wherein at least of two of said wires are formedinto a repositioning and/or retrieval loop having an elongated portioncircumferentially disposed at said first opposed open end; and whereinsaid reposition and/or retrieval loop comprises two sections which runadjacent to each other prior to crossing; grabbing of both sections saidreposition and/or retrieval loop simultaneously to reposition and/orretrieve said stent.
 48. The method of claim 47, wherein the step ofgrabbing further includes using forceps to both sections said repositionand/or retrieval loop.